Topical application of T-2 toxin inhibits the contact hypersensitivity response in BALB/c mice

T-2 toxin, a trichothecene mycotoxin, has previously been shown to alter immune functions and promote skin tumors. We demonstrate that topically applied T-2 toxin reduces the ear swelling response to oxazolone challenge in BALB/c mice. For this reduction in ear swelling to occur, toxin application must be at, or within, 1 h after challenge. Dose-response studies showed a 44% reduction in ear swelling with 30 ng of T-2 toxin as compared with a similar reduction with 300 ng of dexamethasone. T-2 toxin did not affect Ag transport from the challenge site to the draining lymph nodes as measured by FITC transport. However, T-2 toxin significantly reduced both MHC class II (Ia) expression and Ag presentation at the same concentrations. Because T-2 toxin, a known protein synthesis inhibitor, was found to inhibit protein synthesis in epidermal cell cultures as measured by [3H]-leucine incorporation, cycloheximide was also examined. Cycloheximide reduced both oxazolone-induced ear swelling and Ag presentation in a similar manner to T-2 toxin. One mechanism of action for T-2 toxin in reducing the contact hypersensitivity response is via inhibition of protein synthesis and effective Ag presentation by epidermal Langerhans cells. This may involve alterations in Ia Ag expression, although a role for class II in the induction phase of the contact hypersensitivity response has not been established definitively.     

A pilot study of preoperative chemoradiation for patients with localized adenocarcinoma of the pancreas

BACKGROUND: We hypothesized that delivering adjuvant radiotherapy (RT) preoperatively with chemotherapy might enhance local control of the cancer and patient tolerance for the intervention. METHODS: Thirty-four patients with localized pancreatic cancer (24 head, 8 head and body, 2 body and tail) were treated during the past 6 years with an intramural protocol consisting of 5-fluorouracil (1,000 mg/m2 on days 2 to 5 and 29 to 32) and mitomycin-C (10 mg/m2 on day 2) given with preoperative external beam RT (median 5,040 cGy). Nine patients did not have surgery: 1 refused, 1 died of cholangitis, and 7 were noted to have distant (5) or unresectable local cancer (2) after RT. Of the 25 patients who underwent celiotomy, 11 had liver (8) or peritoneal (3) metastases and 3 had palliative pancreatectomies (2 with liver metastasectomy and 1 with hepatic artery and portal vein replacement). The remaining 11 patients (44% of the cohort with surgery, 32% of all patients) had potentially curative (PC) resections (5 total pancreatectomy, 5 Whipple, 1 distal pancreatectomy). Median tumor diameter by computed tomographic scan was 3.75 cm (range 3 to 5) for the 11 patients who received PC resections and 4.5 cm (range 3 to 7.5) for all patients. Of the 11 patients with PC resections, 8 had evidence of superior mesenteric, portal or splenic venous involvement and 4 had been deemed unresectable at previous celiotomies. RESULTS: One patient developed respiratory failure and one died postoperatively, yielding a 9% rate of major morbidity and mortality. Median follow-up of the surviving patients with curative resection is 33 months (range 14 to 70). Their median survival from the time of tissue diagnosis is 45 months with a median disease-free survival of 27 months. The product limit estimate of 5-year survival is 40% (95% confidence bounds +29%, -30%). One patient had a microscopically positive resection margin, which was a falsely negative frozen section margin at the pancreatic neck. Two patients had positive regional lymph nodes. Five patients have been diagnosed with recurrent cancer. Only 1 has had a local/regional component to the recurrence. CONCLUSIONS: Preoperative RT and chemotherapy followed by resection is well tolerated and safe for patients with locally advanced pancreatic cancer. This approach provides tumor free resection margins and offers prolonged survival to patients with truly localized pancreatic cancer.     

Fluorescence in situ hybridization mapping of translocations and deletions involving the short arm of human chromosome 12 in malignant hematologic diseases

Translocations and deletions of the short arm of chromosome 12 [t(12p) and del(12p)] are common recurring abnormalities in a broad spectrum of hematologic malignant diseases. We studied 20 patients and one cell line whose cells contained 12p13 translocations and/or 12p deletions using fluorescence in situ hybridization (FISH) with phage, plasmid, and cosmid probes that we previously mapped and ordered on 12p12-13. FISH analysis showed that the 12p13 translocation breakpoints were clustered between two cosmids, D12S133 and D12S142, in 11 of 12 patients and in one cell line. FISH analysis of 11 patients with deletions demonstrated that the deletions were interstitial rather than terminal and that the distal part of 12p12, including the GDI-D4 gene and D12S54 marker, was deleted in all 11 patients. Moreover, FISH analysis showed that cells from 3 of these patients contained both a del(12p) and a 12p13 translocation and that the affected regions of these rearrangements appeared to overlap. We identified three yeast artificial chromosome (YAC) clones that span all the 12p13 translocation breakpoints mapped between D12S133 and D12S142. They have inserts of human DNA between 1.39 and 1.67 Mb. Because the region between D12S133 and D12S142 also represents the telomeric border of the smallest commonly deleted region of 12p, we also studied patients with a del(12p) using these YACs. The smallest YAC, 964c10, was deleted in 8 of 9 patients studied. In the other patient, the YAC labeled the del(12p) chromosome more weakly than the normal chromosome 12, suggesting that a part of the YAC was deleted. Thus, most 12p13 translocation breakpoints were clustered within the sequences contained in the 1.39 Mb YAC and this YAC appears to include the telomeric border of the smallest commonly deleted region. Whether the same gene is involved in both the translocations and deletions is presently unknown.     

Respiratory health hazards and lung function in wildland firefighters

The authors discuss the multitude of contaminants to which wildland firefighters are exposed, including carbon monoxide, sulfur dioxide, particulate and silica, polyaromatic hydrocarbons, aldehydes, and benzene. They examine the respiratory effects of these contaminants and then present their recommendations for an occupational health program for wildland firefighters.     

Cough induced by quinapril with resolution after changing to fosinopril

OBJECTIVE: To report a case of chronic, nonproductive cough secondary to the angiotensin-converting enzyme (ACE) inhibitor quinapril, with complete resolution after switching to another ACE inhibitor, fosinopril. DATA SOURCES: All relevant articles from January 1985 through February 1993 were identified, primarily through MEDLINE search and review of pertinent articles' bibliographies. CASE SUMMARY: A 68-year-old woman developed a dry, irritating cough within one month of starting quinapril therapy for the treatment of essential hypertension. The patient was a nonsmoker with no respiratory illnesses. The cough continued for the duration of therapy with quinapril. One month after changing to fosinopril therapy, the patient reported complete resolution of the cough. She remains cough-free to date. DISCUSSION: Cough induced by ACE inhibitors is a frequently documented adverse effect. It is severe enough to require discontinuation of therapy in 1-10 percent of patients. The cough is considered to be a class-related adverse effect with cross-reactions between ACE inhibitors routinely reported. At this time, changing to another ACE inhibitor or additive therapy with nonsteroidal antiinflammatory drugs is not recommended. Discontinuation of the ACE inhibitor results in rapid alleviation of the cough, although this is not always necessary, as most patients may experience a cessation or decrease in cough. We report a case of cough following the administration of quinapril, with complete resolution after changing to the alternative ACE inhibitor fosinopril in a patient with essential hypertension. CONCLUSIONS: Cough has been encountered commonly after the administration of ACE inhibitors. Frequency of cough is variable and although this complication has been described as a class effect, patients with a persistent, severe ACE inhibitor-induced cough may benefit from a trial of fosinopril therapy. This may be particularly useful in patients unable to tolerate an alternative class of antihypertensive agents.     

Causes of cervical carcinoma: new ideas

There are many features of cervical cancer that distinguish it from other common human cancers. It is extraordinarily sensitive to environmental variation, thus coming under early notice by the epidemiologists. Its accessibility and the introduction of aids to visualization, such as the colposcope, have enabled us to combine the methods of epidemiology and molecular biology in studying disease. This combination may well untangle one of the more serious conceptual problems in contemporary biology - the real nature of the carcinogenic process and all this in man himself.     

Scanning microscopy of pituitary vascular casts

Vascular casts of the pituitary-median eminence complex from seventeen adult female rabbits were examined with the scanning electron microscope. The results of this study confirm the presence of a single capillary bed common to the entire neurohypophysis. Arterial supply to the rabbit pituitary is only to the neurohypophysis. A direct supply to adenohypophysis was not found. Within the median eminence there are an external and internal capillary plexus. The internal capillary plexus is directed toward the infundibular recess of the third ventricle. It does not receive a direct arterial supply but derives its blood supply from the external plexus before draining to the adenohypophysis. Vessels of the posterior median eminence are confluent with vessels of the infundibular stem. On the basis of these studies, it is proposed that the entire neurohypophysis, not simply the median eminence, serves as the final common pathway to the glandular pituitary. It is also proposed that in the median eminence, vessels are organized to deliver blood containing hypothalamic releasing and inhibiting hormones as well as posterior lobe neural hormones (antidiuretic hormone and oxytocin) to the ventricular surface for subsequent transport to cerebrospinal fluid and distribution to the brain.