Expression cloning of a human brain neuropeptide Y Y2 receptor

The 36-amino acid peptide, neuropeptide Y (NPY), is a member of a peptide family that includes the endocrine peptides, peptide YY (PYY), and pancreatic polypeptide (PP). NPY receptors have been broadly subdivided into postsynaptic Y1 receptors and presynaptic Y2 receptors based on the preference of Pro34-substituted analogues for the Y1 receptors and carboxyl-terminal fragments for the Y2. A Y1 receptor has been cloned, and this receptor appears to mediate several effects of NPY, including vasoconstriction and anxiolysis in animal models. We report the cloning of a human brain Y2 receptor from a human brain library. Pools of clones were transiently expressed in COS-1 cells, and 125I-PYY binding pools were identified by autoradiography. After a single positive pool was detected in the original screening, a single clone was isolated by four rounds of sequential enrichment. The clone encoded a 381-amino acid protein of the heptahelix (seven TM) type. Amino acid identity of this receptor with the Y1 receptor was 31% overall with 40% identity in the TM regions. Comparison with the human PP1 receptor indicated 33% overall amino acid identity with 42% identity in the TM regions. Pharmacologically, the receptor exhibited high affinity for NPY, PYY, and carboxyl-terminal fragments of NPY and PYY. In addition, Pro34-substituted analogues had very low affinity. With the use of Northern blot analysis, high levels of Y2 mRNA were detected in a variety of brain regions with little expression in peripheral tissues. Thus, the receptor protein has the pharmacological properties and distribution of the human Y2 receptor.     

Provider choice and continuity for the treatment of depression

The role of specialist versus generalist providers regularly surfaces in health-care reform debates about costs and quality of care. By changing incentives to seek and deliver care, different payments systems can affect both the probability of initial specialty care and the duration of this patient-provider relationship. The authors compare provider selection (psychiatrist, nonphysician mental-health specialist, general medical provider) and duration of this relationship among depressed patients in prepaid and fee-for-service plans. Regarding initial care, depressed patients in prepaid plans are significantly less likely to see a psychiatrist and more likely to see a nonphysician mental-health specialist than patients in fee-for-service plans. Although the mix of providers differs, patient demographic and clinical characteristics have similar effects on specialty in both payment systems, ie, there are no differences in who gets specialty care by type of payment, but in how many get specialty care. The average duration of a patient-provider relationship is significantly shorter in prepaid plans. Durations are significantly shorter for patients of both psychiatrists and general medical providers in prepaid plans, but do not differ by payments type for nonphysician therapists. In both payments systems, patients of nonphysician providers end the relationship sooner than patients of psychiatrists or general medical providers. Although the authors find provider switching to be associated significantly with discontinuing antidepressant medication, there is no significant direct effect on patient health outcomes.     

Heart transplantation in patients with diabetic end-organ damage before transplantation

Diabetes mellitus with preexisting end-organ damage (EOD) is considered a contraindication for heart transplantation. The outcome of such patients has not been well characterized. Among 138 patients transplanted between 12/88 and 7/94, 29 were diabetic (11 insulin-dependent); of these, 12 had preexisting EOD, defined as a creatinine clearance < or = 50 ml/min, a 24-hour urine protein concentration > or = 500 mg/L or typical symptoms of peripheral or autonomic polyneuropathy, and 17 had no EOD. We compared diabetics with and without EOD and non-diabetics (n = 109) for operative mortality, length of stay, serum creatinine, fasting glucose levels, and postoperative prednisone doses at 1,6, and 12 months. Actuarial survival and freedom from rejection and infection were analyzed. Both diabetic groups were significantly older than nondiabetics, Ischemic time, operative mortality, surgical technique, ICU- and total length of stay were similar. Actuarial survival and freedom from rejection were similar among the three groups. Infection rates including CMV did not differ. Serum creatinine levels increased in all groups compared to pretransplant levels (p = 0.001), but without significant differences among the groups. Post-transplant glucose levels at 6 and 12 months were higher for diabetic patients with EOD than for those without or for nondiabetics (183, 153, and 94 mg/dl at 6 months, p = 0.01; 202, 161, and 102 mg/dl at 12 months, p = 0.0001). Prednisone dosage was lower in diabetics with EOD at 6 months, but did not differ among the three groups at 12 months. The incidence of angiographically proven transplant vasculopathy did not differ at 1 and 2 years. Diabetics with preexisting EOD undergoing heart transplantation experience similar short- and intermediate-term results when compared to diabetics without EOD and nondiabetics. Metabolic control is more difficult to achieve, as indicated by higher fasting glucose levels. Larger and longer-term prospective studies have to confirm our findings, since the shortage of donor organs would increase if such patients were transplanted routinely.     

Virus-specific interaction between the human cytomegalovirus major capsid protein and the C terminus of the assembly protein precursor

We previously identified a minimal 12-amino-acid domain in the C terminus of the herpes simplex virus type 1 (HSV-1) scaffolding protein which is required for interaction with the HSV-1 major capsid protein. An alpha-helical structure which maximizes the hydropathicity of the minimal domain is required for the interaction. To address whether cytomegalovirus (CMV) utilizes the same strategy for capsid assembly, several glutathione S-transferase fusion proteins to the C terminus of the CMV assembly protein precursor were produced and purified from bacterial cells. The study showed that the glutathione S-transferase fusion containing 16 amino acids near the C-terminal end was sufficient to interact with the major capsid protein. Interestingly, no cross-interaction between HSV-1 and CMV could be detected. Mutation analysis revealed that a three-amino-acid region at the N-terminal side of the central Phe residue of the CMV interaction domain played a role in determining the viral specificity of the interaction. When this region was converted so as to correspond to that of HSV-1, the CMV assembly protein domain lost its ability to interact with the CMV major capsid protein but gained full interaction with the HSV-1 major capsid protein. To address whether the minimal interaction domain of the CMV assembly protein forms an alpha-helical structure similar to that in HSV-1, peptide competition experiments were carried out. The results showed that a cyclic peptide derived from the interaction domain with a constrained (alpha-helical structure competed for interaction with the major capsid protein much more efficiently than the unconstrained linear peptide. In contrast, a cyclic peptide containing an Ala substitution for the critical Phe residue did not compete for the interaction at all. The results of this study suggest that (i) CMV may have developed a strategy similar to that of HSV-1 for capsid assembly; (ii) the minimal interaction motif in the CMV assembly protein requires an alpha-helix for efficient interaction with the major capsid protein; and (iii) the Phe residue in the CMV minimal interaction domain is critical for interaction with the major capsid protein.     

Absorption, tissue distribution, and excretion of zinc acexamate in rats

AIM: The SRK II formula has been widely used for intraocular lens (IOL) power calculations. The predictability of this formula is evaluated in axial myopic patients. METHODS: Planned extracapsular cataract extraction and posterior chamber IOL implantation (PECCE + IOL) were performed on 98 eyes of 98 patients with axial length > 24.5 mm. Cases had no preoperative complications and postoperative visual acuity was at least 0.5 (Snellen). Corneal refractive power and axial length were measured preoperatively and emmetropic IOL power calculations were made using the SRK II formula. Long-term (mean 4.7 months) visual acuities and refractions were noted postoperatively. RESULTS: The absolute refractive error was < 1.00 Diopters (D) in 57 eyes (58.2%) and < 2.00 D in 83 eyes (84.7%). The mean absolute error of the SRK II formula in axial myopia was 1.16 D +/- 0.78 SD. CONCLUSIONS: The SRK II formula is not very accurate in axial myopic patients.     

Evaluation of choroidal neovascularization in age-related macular degeneration with fluorescein and indocyanine green videoangiography

375 Individuals from 23 HBsAg positive families were investigated in the study. The results showed that HBsAg carrier rate among blood relatives was significantly higher than non-blood relatives (P < 0.01); HBsAg carrier rate decreased with the order of the first, second and third degree relatives (P < 0.01); and the rate in the individuals living together with the probands was higher than those living apart (P < 0.01). However, the other two markers of HBV infectivity, anti-HBs and anti-HBc, did not show any differences mentioned above. The results analysed by means of dichotomy and Logistic regression model, showed that blood relationship played an important role in HBsAg carrier state. In addition, the history of sharing living facilities was related to HBsAg carrier state. The average heritability in the first, second and third degree relatives was 79.68%. The analysis of genetic model showed that HBsAg carrier state was corresponded to the characteristic of multifactorial genetic disease, excluding the possibility of genetic disease due to single gene.     

Local TH1 and TH2 responses to parasitic infection in the intestine: regulation by IFN-gamma and IL-4

Control of parasitic infections is dependent on the production of cytokines that activate mechanisms which limit invasion, reproduction or survival of the parasite. In contrast, conditions that induce inappropriate cytokine responses facilitate the spread of infection and ultimately exacerbate the level of disease. Measurement of local cytokine responses to different gastrointestinal parasites, such as the intracellular protozoan, Cryptosporidium parvum, and luminal dwelling nematodes like Nippostrongylus brasiliensis and Heligmosomoides polygyrus, reveal stereotype response patterns. In general, intracellular parasites stimulate type 1 responses where IFN-gamma is the predominant immune activator, while extracellular parasites stimulate type 2 responses where IL-4 plays a prominent role in elevating humoral immune mechanisms. Cytokines alter cellular function and the milieu of the intestinal lumen to affect the outcome of an infection. The importance of a particular response during the course of an infection can be studied by selective enhancement with an excess of exogenous recombinant cytokine or cytokine antagonists. For example, exogenous IL-12 enhances resistance to C.parvum, but suppresses the normally rapid cure of an infection with N. brasiliensis. Both mechanisms are dependent on expression of IFN-gamma. At the molecular level, exogenous IL-12 stimulates IFN-gamma production which elevates a protective type 1 response to C. parvum but converts the normally anti-worm type 2 response to a type 1 response that inappropriately regulates the infection. Alternatively, excess IL-4 plays a prominent role in modulating effector elements that change intestinal physiology to create a hostile environment for worm parasites. Exogenous IL-4 can cure chronic worm infection, while IL-4 antagonists interfere with protective responses to infection. These observations provide a paradigm for analysis of stereotype responses to different gastrointestinal parasites, and demonstrate how cytokine-induced immune system-dependent and independent effector mechanisms can limit parasitic infection, while inappropriate cytokine responses can exacerbate the state of disease.     

Age at onset of puberty following high-dose central nervous system radiation therapy

OBJECTIVE: To determine if a relationship exists between age at irradiation, sex of the patient, and age at onset of puberty and pubarche in children treated with high-dose radiation to the central nervous system. DESIGN: Case series. SETTING: Tertiary care institutional practices and clinics. PATIENTS: Thirty-six children treated with high-dose irradiation (hypothalamic pituitary dose, 30-72 Gy) by conventional (n = 29) or hyperfractionated (n = 7) schedules. Girls were treated before age 8 years and boys before age 9 years. Twenty-six of the 36 children also received chemotherapy. All tumors were distant from the hypothalamic-pituitary region. MAIN OUTCOME MEASURE: Age at onset of puberty and pubarche. RESULTS: In girls, the median age at onset of puberty was 9.3 years vs 10.9 years for controls (P < .01); pubarche occurred at 9.4 years vs 11.2 years for controls (P < .01). In boys, the median age at onset of puberty--genital II--was 11.0 years vs 11.5 years for controls (P = .30); pubarche occurred at a median age of 10.5 years vs 12 years for controls (P = .25). A censored-data normal linear regression model was used to account for children (n = 6) who had not reached puberty. Age at diagnosis (P < .01) and sex (P = .01) were significant predictors of age at onset of puberty. Body mass index SD score (z score) was inversely related to age at onset of puberty (r = -0.77) and was greater at onset of puberty in girls than in boys. CONCLUSION: In children who have received high-dose cranial radiation therapy, a significant positive correlation exists between age at diagnosis and age at onset of puberty in boys and girls.