An outbreak of refrigerant-induced acute hepatitis in Hong Kong

We report a cluster of acute hepatitis in five air-conditioning maintenance workers following accidental exposure to 2,2-dichloro-1,1,1-trifluoroethane (HCFC-123). They presented to us with complaints of feverishness, generalised malaise, and epigastric discomfort. Their blood biochemistry tests were compatible with acute hepatitis. Viral hepatitis serology, tests for autoimmune hepatitis, and analyses for drugs and alcohol consumption were all negative. No focal hepatic lesion was detected by ultrasound imaging. Percutaneous liver biopsy samples were taken from two of them. The patients were managed with supportive treatment. All had spontaneous, but slow, recovery. Their liver function tests returned to normal after 4 months and their outcomes were favourable. Physicians should be aware of this occupational disease entity.

Development of the skeletal system

The analysis of the development of the skeletal system has been greatly facilitated by the availability of a large number of mouse mutants with skeletal defects. Whereas for many of these mutants a description of the main phenotypic abnormalities is known, molecular insight into the ontogeny of the skeletal system is limited. One of the few skeletal mutants for which the molecular basis is known is undulated. These mice have a defect in the differentiation of the sclerotome and Pax-1, a mouse paired-box containing gene, has been identified as a candidate gene for this mutation. A molecular analysis of three independent undulated alleles revealed that in each case the Pax-1 gene is affected. One of the alleles could be classified as a null allele, in which the Pax-1 gene is deleted. A phenotypic analysis shows that Pax-1 is required for proper differentiation of intervertebral discs and vertebral bodies.

Pseudomembranous colitis without diarrhoea following Helicobacter pylori eradication therapy

A 73-year-old man with a known history of hypertension and gout was admitted into hospital having had chest and epigastric discomfort for 3 days. His chest discomfort was not related to exertion, and there was no recent history of antibiotic or non-steroidal anti-inflammatory drug intake. His bowel habit was normal. Physical examination was unremarkable except for mild ankle oedema. Per rectum examination revealed brownish stool and no mass was felt.

Intestinal obstruction and gastrointestinal bleeding due to systemic amyloidosis in a woman with occult plasma cell dyscrasia

A 60-year-old woman presented to our hospital with repeated vomiting. Upper gastrointestinal endoscopy revealed a 1 cm diameter ulcer with clean base on the roof of the gastric antrum. Histological examination of gastric biopsies revealed abundant amorphous eosinophilic deposits in the submucosa. Congo red stain for amyloid was positive. A barium follow-through study revealed a mass in the jejunum causing incomplete obstruction. Urine for Bence Jones protein was negative. Serum protein electrophoresis did not reveal any abnormal band and serum immunoelectrophoresis did not detect any monoclonal immunoglobulin. Bone marrow examination, however, revealed an increased proportion of plasma cells. Subsequent immunohistochemical staining demonstrated monoclonal lambda light chains in the marrow plasma cells, thereby confirming a plasma cell dyscrasia. Amyloidosis involving the gastrointestinal tract can produce a wide variety of non-specific symptoms and signs. A high index of suspicion is necessary to arrive at an early diagnosis. Management consists of supportive therapy for the gastrointestinal tract as well as treatment of the underlying condition.

Gastric polypoid lesions--illustrative cases and literature review

Currently, upper gastrointestinal endoscopies are frequently performed for patients with various gastrointestinal symptoms. From time to time, lumps and bumps in the stomach are encountered on endoscopy. Four cases of gastric polypoid lesions are presented. The classification, differentiation, and management approach to these lesions are discussed. Although there is consensus that all gastric adenomatous polyps should be removed, as should gastric hyperplastic polyps that are symptomatic and/or bear dysplastic foci on forceps biopsy, controversy still exists over the management of asymptomatic gastric hyperplastic polyps that do not bear any dysplastic focus on forceps biopsies. Endoscopic ultrasonography (EUS) has a promising role in the evaluation of gastric submucosal polypoid lesions.

A case of colonic tuberculosis mimicking Crohn's disease

A 26-year-old Thai woman who has lived in Hong Kong for the past 3 years presented with a 2-month history of feverishness, intermittent epigastric discomfort, anorexia, and weight loss. She had had per rectal bleeding for 10 days. Colonoscopy on two separate occasions revealed multiple ulcerations involving the entire colon, with rectal sparing. Histological examination of the two sets of colonic biopsies that were obtained during colonoscopy suggested Crohn's disease. There was no response to mesalazine and metronidazole, but the patient responded promptly to a therapeutic trial of antituberculous drugs. Cultures from the first set of colonic biopsies were negative for acid-fast bacilli, but 8 weeks after the second colonoscopy, cultures from the second set of biopsies yielded Mycobacterium tuberculosis. This case illustrates that the diagnosis of colonic tuberculosis requires a high index of suspicion. In cases where the information available does not reveal a definite differentiation between colonic tuberculosis and Crohn's disease, corticosteroids should be withheld. The administration of corticosteroids to a patient with colonic tuberculosis may have disastrous results, and a therapeutic trial of antituberculous drugs should be considered instead.

Embryologic and cytogenetic effects of ethanol on preimplantation mouse embryos in vitro

Ethanol and its primary metabolite acetaldehyde were studied in cultured preimplantation mouse embryos with respect to embryotoxicity, embryolethality, chromosome breaking activities, and ability to induce sister chromatid exchange (SCE). Analysis of differentiation and cell number of mouse morulae and blastocysts show that acetaldehyde is three orders of magnitude more toxic than ethanol, indicating that the metabolite is responsible for the embryotoxicity of ethanol in preimplantation embryos. Concentrations of ethanol that do not inhibit growth induce SCEs and chromosome aberrations. The SCE-inducing effect of ethanol disappears in the presence of 4-methylpyrazole (4-MP), an inhibitor of alcohol dehydrogenase (ADH). These data suggest that preimplantation embryos are able to convert ethanol to acetaldehyde and that ADH is the enzyme involved. It is, furthermore, shown histochemically that mouse oocytes as well as morulae and blastocysts are able to oxidize ethanol in the presence of NAD+.

Excess volumes of dimethyl sulphoxide mixtures

The volumes of mixing (excess volumes) for dimethyl sulphoxide with carbon tetrachloride, chloroform, benzene, acetone, and water have been measured at 25.00� and 35.00� with a dilatometer. The values for the equimolar mixtures at 25.000 are -0.596, -0.112, -0.304, -0.511, and -0.944 cm3 mol-1 respectively. The results are compared with available density measurements on these systems and qualitatively compared with the corresponding acetone systems.