Treatment of hypertension in the presence of coexisting medical conditions

Treating hypertension reduces morbidity and mortality. Unfortunately, hypertension often exists in patients with other medical conditions. In these patients, the selection of an antihypertensive agent is often influenced by the presence of the coexisting condition. Conversely, the treatment of the coexisting medical condition may be influenced by the presence of hypertension. Given the vast array of antihypertensive medications available today, appropriate treatment of both hypertension and coexisting conditions can be achieved with careful selection of medications. This review discusses factors to consider when treating elderly patients with hypertension with the following coexisting conditions: dyslipidaemia, glucose intolerance, sexual dysfunction, cardiovascular disease, pulmonary disease, renal disease and neuropsychiatric disorders. Hypothyroidism, hyperthyroidism and various states of high cardiac output may cause hypertension. These conditions should be identified, since they are often treatable with subsequent resolution of the hypertension.     

Role of zinc during hamster sperm capacitation

Zinc stabilizes somatic cell membranes and DNA, inhibits respiration, is present in high concentrations in the male reproductive tract, and may stabilize sperm during storage and ejaculation. Zinc removal from sperm may be necessary to prepare sperm for fertilization (capacitation). Incubation with Zn2+ chelators, e.g., D-penicillamine, can capacitate hamster sperm (Andrews and Bavister, Gamete Res 1989; 23:159-70). In the present study, the Zn(2+)-specific fluorochrome N-(6-methoxy-8-quinolyl)-p-toluenesulfonamide (TSQ) and the vital stain propidium iodide were used to assess the zinc content of live hamster sperm with flow cytometry before and after capacitation. Capacitation was monitored with a salt-stored zona pellucida penetration assay or the occurrence of spontaneous or induced (with lysophosphatidylcholine) acrosome reactions. The effect of added zinc on sperm capacitation was also evaluated. Image Analysis was used to determine the subcellular location of zinc (TSQ fluorescence) and atomic absorption to determine whether the total zinc content of sperm changes during capacitation. Sperm incubated under non-capacitating conditions had high TSQ fluorescence and could not penetrate zonae pellucidae. Sperm incubated under capacitating conditions (plus BSA or D-penicillamine) were zinc-depleted (low fluorescence) and penetrated 90% or 78% of zonae, respectively. Image analysis showed a significant reduction in zinc in the acrosomal region during capacitation with BSA, but this did not correlate with the occurrence of spontaneous acrosome reactions. The atomic absorption data showed that the total zinc content of sperm was reduced by 44% or 40% when sperm were incubated under capacitating conditions (BSA or D-penicillamine, respectively). Zona pellucida penetration was completely inhibited when zinc was present throughout the capacitation period but not when it was added at the end of incubation. These data indicate that removal of zinc from hamster sperm is correlated with capacitation and may play a key regulatory role in this process.     

Effects of WB4101 and chloroethylclonidine on the positive and negative inotropic actions of phenylephrine in rat cardiac muscle

This study was designed to determine if the positive and negative inotropic actions of alpha-1-adrenergic agonists in rat atrial and ventricular myocardium are mediated via different alpha-1-adrenergic receptor (AR) subtypes. Inotropic effects of phenylephrine were examined in isolated left atrial and papillary muscle before and after treatment with prazosin, WB4101 (N-[2-(2,6-dimethoxyphenoxy)ethyl]-2,3-dihydro-1,4-benzodioxin+ ++-2-methanamine), chloroethylclonidine (CEC) and WB4101 plus CEC. Phenylephrine (10 microM) elicited a monophasic positive inotropic response in left atrial muscle and a triphasic inotropic action in papillary muscle (transient positive, then negative inotropic components preceding a sustained positive inotropic response). CEC, WB4101 and prazosin each antagonized the monophasic response in isolated left atria and the sustained positive inotropic response in papillary muscle. CEC and prazosin each antagonized the transient negative inotropic component in papillary muscle. The transient positive inotropic response was not affected by CEC, WB4101 or CEC plus WB4101, but was antagonized by higher concentrations of prazosin. These data suggest that the sustained positive inotropic effect of alpha-1-adrenergic agonists in rat atrial and ventricular myocardium results from stimulation of alpha-1A and alpha-1B ARs, whereas the transient negative inotropic component of the triphasic response in ventricular preparations is mediated via alpha-1B ARs. However, present data do not exclude the possibility that the CEC-sensitive inotropic responses elicited by phenylephrine may be mediated in part by other recently described alpha-1 subtypes. The receptors involved in the transient positive inotropic action cannot be identified by current results.     

Uncemented total shoulder arthroplasty. A review

Clinicians have had much experience with uncemented humeral components. A press-fitted humeral component will usually remain stable in the absence of a glenoid component. From the information available, surgeons should not continue to use press-fitted humeral components for total shoulder arthroplasty. Tissue ingrowth humeral components offer promise; however, the reports to date have short or intermediate length followup, and radiographic results do not equal those of cemented components. Early clinical results with tissue ingrowth glenoid components are excellent; radiographically evident changes occur much less frequently than they do following cement fixation. However, their disadvantage is the possibility of accelerated polyethylene wear and subsequent metal-induced synovitis. As such, there are no clear cut indications for cement fixation versus tissue ingrowth fixation for the glenoid component other than those intuitively based on bone quality and quantity in the glenoid fossa. Accruing experience will help to define the indications better, but given the similarity of clinical outcomes to date, distinction between the options may be difficult.     

Antimicrobial strategies in the care of organ transplant recipients

OBJECTIVE: To evaluate amniotic fluid lamellar body counting as a fetal lung maturity test. Lamellar body particles can be rapidly counted using the platelet channel of most blood cell analyzers. METHODS: We conducted a 3-year prospective clinical outcome study. During the interval under study, outcomes of 247 neonates were used to evaluate the test; 28 neonates developed respiratory distress syndrome (RDS). Lecithin-sphingomyelin ratio (L/S) was available for 187 cases. RESULTS: All cases of RDS had lamellar body counts of 55,000/microL or less and L/S of 2.2 or less; 59% of cases with no RDS had counts greater than 55,000/microL and 70% of normal cases had L/S higher than 2.2. CONCLUSION: Use of lamellar body counts is justified as a rapid screening test to predict fetal lung maturity. Immature results should be followed by a more specific test such as L/S.     

Long survival with giant cell myocarditis

Several aspects of giant cell myocarditis remain controversial, including the natural history of the disease and the nature of the giant cells. We have observed three patients who had long survival with chronic active giant cell myocarditis. The first patient was a 59-yr-old female who had a 10-yr history of complete heart block which was found at autopsy to have been caused by giant cell myocarditis. The second patient is a 36-yr-old female who received a heart transplant 5 yr after a biopsy proven episode of active myocarditis, and examination of the explanted heart revealed giant cell myocarditis. The third patient was a 41-yr-old male who received a heart transplant 2 yr after developing progressive heart failure, and the explanted heart had giant cell myocarditis. On immunohistochemical study of the three hearts, the giant cells stained with the macrophage markers lysozyme and KP-1 (CD-68). Staining of the same cells with desmin and actin was focally positive in a punctate pattern, correlating with the ultrastructural presence of myofibrils within giant cell phagolysosomes. The associated lymphocytic infiltrate stained primarily for the T-cell markers CD-3, CD-45RO, and CD-43 whereas only a few of the lymphocytes stained with the B-cell marker CD-20. The long histories of cardiac dysfunction in the three patients show that giant cell myocarditis may have a protracted course. The morphologic studies show that the giant cells are of histiocytic origin but can contain phagocytosed components of myocytes, observations that may account for the controversy surrounding the nature of the giant cells in giant cell myocarditis.     

Enzyme variation at the aspartate aminotransferase locus in members of the Anopheles gambiae complex (Diptera: Culicidae)

The enzyme aspartate aminotransferase (AAT) currently is used to identify Anopheles quadriannulatus Theobald, the animal-biting, nonmalaria vector species of the Anopheles gambiae complex. Samples of An. quadriannulatus from South Africa and An. gambiae Giles s.str. from the island of Grand Comoros and the People's Republic of Congo have shown variation in electromorph frequencies that indicate that AAT has five alleles. The three slowest alleles are found in An. quadriannulatus and the three fastest in An. gambiae, An. arabiensis Patton and An. merus D?nitz. One of these is common to both An. quadriannulatus and An. gambiae. This overlap indicates a potential misidentification of 0.3% of unknown females with a further 2.1% being unidentifiable. However, all of the specimens in the overlap area were classified correctly using octanol dehydrogenase (ODH). Variation at the ODH locus in An. quadriannulatus is recorded for the first time, with four of 157 specimens being heterozygous for the fast allele. The probability of both AAT and ODH giving an incorrect or indecisive identification is 0.0005. The slowest AAT alleles were present in samples from a single locality, indicating the lack of gene flow between subpopulations of An. quadriannulatus in close geographic proximity in the Shingwedzi area, South Africa. A modified method for multiple gel casting is given.