Cellular localization of membrane-type serine protease 1 and identification of protease-activated receptor-2 and single-chain urokinase-type plasminogen activator as substrates.

Membrane-type serine protease 1 (MT-SP1) was recently cloned, and we now report its biochemical characterization. MT-SP1 is predicted to be a type II transmembrane protein with an extracellular protease domain. This localization was experimentally verified using immunofluorescent microscopy and a cell-surface biotinylation technique. The substrate specificity of MT-SP1 was determined using a positional scanning-synthetic combinatorial library and substrate phage techniques. The preferred cleavage sequences were found to be (P4-(Arg/Lys)P3-(X)P2-(Ser)P1-(Arg)P1'-(Ala)) and (P4-(X)P3-(Arg/Lys)P2-(Ser)P1(Arg) P1'(Ala)), where X is a non-basic amino acid. Protease-activated receptor 2 (PAR2) and single-chain urokinase-type plasminogen activator are proteins that are localized to the extracellular surface and contain the preferred MT-SP1 cleavage sequence. The ability of MT-SP1 to activate PARs was assessed by exposing PAR-expressing Xenopus oocytes to the soluble MT-SP1 protease domain. The latter triggered calcium signaling in PAR2-expressing oocytes at 10 nm but failed to trigger calcium signaling in oocytes expressing PAR1, PAR3, or PAR4 at 100 nm. Single-chain urokinase-type plasminogen activator was activated using catalytic amounts of MT-SP1 (1 nm), but plasminogen was not cleaved under similar conditions. The membrane localization of MT-SP1 and its affinity for these key extracellular substrates suggests a role of the proteolytic activity in regulatory events.

Histological findings in a case of alobar holoprosencephaly diagnosed at 10 weeks of pregnancy.

A case of alobar holoprosencephaly diagnosed at 10 + 3 weeks' gestation by transabdominal and transvaginal ultrasound examination followed by histological confirmation is presented. The diagnosis was based on two sonographic criteria: intracranial finding of a single ventricle with a mantle and no visible midline structures but fusion of the thalami and corpus striatum, and facial abnormalities, including hypotelorism and proboscis. The fetal karyotype was triploidy. The ultrasound findings were confirmed by pathological examination. The histological findings of proboscis, single lens and single ventricle with neural tissue remnants are presented.

First-trimester ultrasound diagnosis of holoprosencephaly: three case reports.

We present three cases of fetal holoprosencephaly diagnosed by transabdominal and transvaginal ultrasound examinations at 10 and 13 weeks' gestation. The diagnosis was based on two sonographic criteria: first, the intracranial finding of a single ventricle with a cerebral mantle and no visible midline structures but fusion of the thalami and corpus striatum; and, second, facial abnormalities, including hypotelorism. The ultrasound findings were confirmed by embryoscopy before abortion in one case and by pathological examination after abortion in two cases. Chromosome study of the three fetuses showed trisomy 18, triploidy and mosaic 18p deletion and duplication.

Fatal accidental aconitine poisoning following ingestion of Chinese herbal medicine: a report of two cases.

Two Hong Kong Chinese adults were prescribed aconitine-containing herbal preparations by Chinese herbal practitioners for relief of minor musculoskeletal pain. After ingestion both quickly developed ventricular tachycardia followed by ventricular fibrillation and cardiac arrest refractory to resuscitation; death in both cases occurred within 12 h of ingestion. Neither had a history of cardiac disease. Coroners' autopsies showed no significant macroscopic or microscopic findings, with no evidence of ischaemic heart disease or other cardiac disease. Toxicological examination of stomach contents showed a trace of hydrolysed aconitine in one case but was negative in the other. Analysis of the herbal preparations consumed, however, confirmed the presence of the aconitine-containing herbs in quantities greatly in excess of the maximum recommended in the P.R. China pharmacopoeia. Both patients therefore consumed an accidental overdose of aconitine, which has a narrow safety margin between therapeutic analgesic effect and its known cardiotoxic effect. These particular herbal medicines are controlled substances in mainland China and Taiwan, but no controls on their dispensing exist in Hong Kong. Together with reported non-fatal cases of aconitine poisoning, these cases emphasise that legal controls of the dispensing and use of aconitine-containing herbal preparations are necessary in Hong Kong.

Vega testing in the diagnosis of allergic conditions. The Australian College of Allergy.

Vega testing (the Vega test method) is an unorthodox method of diagnosing allergic and other diseases. It has no established scientific basis and there are no controlled trials to support its usefulness. Vega testing may lead to inappropriate treatment and expense to the patient and community.

The complementary role of fine needle aspiration cytology and Tru-cut needle biopsy in the management of breast masses.

Fine needle aspiration cytology (FNA) and Tru-cut needle biopsy (TNB) have been used for the pre-operative diagnosis of cancer in breast masses as alternatives to open breast biopsy. The accuracy of clinical examination, fine needle aspiration biopsy and Tru-cut needle biopsy was assessed in 230 patients with palpable breast masses and the value of using both biopsy methods in the management was prospectively evaluated. Clinical diagnosis had a sensitivity of 89.2% and specificity of 78.4% (32.7% false positive, 6.5% false negative). Aspiration cytology was diagnostic in 78.4% of cancers and 71.6% of benign lesions [excluding non-diagnostic samples (27.4%), sensitivity was 96.6% and specificity was 100%]. Tru-cut needle biopsy identified 82.9% of cancers and 61.7% of benign lesions [excluding non-diagnostic samples (33.3%), sensitivity was 96.7% and specificity was 100%]. There were no false positive errors with either aspiration cytology or needle biopsy. Statistical comparison showed that there was no significant difference between aspiration cytology and needle biopsy. The combined result of both biopsies was superior to clinical examination when non-diagnostic samples were excluded. With the routine use of both biopsy techniques, frozen section was avoided in 73% of all cancers and unnecessary operations were avoided in 33.5% of patients which included breast cysts, benign mammary dysplasia and inflammatory lesions.

The clinical significance of proteinuria in patients with nonparasitic chyluria.

Five patients with heavy proteinuria and nonparasitic chyluria due to congenital abnormalities of the lymphatic system are described. Renal biopsies confirmed the clinical suspicion of an underlying glomerulonephritis. The coexistence of glomerulonephritis and chyluria in these patients was thought coincidental. Tests of value in detecting a concomitant glomerulonephritis in these patients with chyluria include urinary RBC morphology, quantitation of 24-hour urinary protein, and immunoelectrophoresis of serum and urinary proteins. Contrary to previous reports, the present study suggests that chyluria does not produce proteinuria of enough severity to cause hypoproteinemia.

The immunochemical characterization of the light chains in the mesangial IgA deposits in IgA nephropathy.

The immunochemical characterization of the light chains of the mesangial immunoglobulin A (IgA) deposits were studied in 45 patients with IgA nephropathy. Kappa and lambda light chains were detected with direct immunofluorescence (IF) method, using monospecific rabbit anti-human anti-kappa and anti-lambda anti-sera. The glomeruli of 42 renal biopsies studied were strongly positive for lambda light chain, while only 25 specimens were positive for kappa light chain. Sixty-five percent of the biopsies showed a predominance of lambda light chain IF staining in the mesangial deposits. This IF pattern is unique as compared with similar studies on renal biopsies from patients with systemic lupus erythematosus, idiopathic membranous nephropathy, and normal postmortem renal tissue. The results indicate that mesangial IgA deposits in IgA nephropathy consist mainly of IgA with lambda light chains despite the fact that the normal ratio of kappa to lambda light-chain-containing immunoglobulin in human serum is two to one.

Bilateral amyloid tumours of the breast.

An 82 year old woman with bilateral amyloid tumours of the breast is described. Clinically, the breast masses were hard and were suspicious of carcinoma. Investigation revealed no evidence of systemic amyloidosis or amyloid related illness. Microscopically there was no neoplasia. Instead there was extensive fibrosis with amyloid deposition in perivascular periductal areas and also in the intervening stroma. The presence of amyloid was confirmed by special stains and by electron microscopy.

Nephrotic range proteinuria--a good predictive index of disease in IgA nephropathy?

A combined retrospective and prospective study of 86 patients with IgA nephropathy was conducted to determine whether the level of proteinuria was a good predictive index of progressive disease. The patients fell into three groups: Group A, 31 patients with proteinuria of less than 1 g/day, Group B, 31 patients with proteinuria of 1 to 3.5 g/day; and Group C, 24 patients with proteinuria of more than 3.5 g/day. The groups are comparable in age of presentation, sex ratio, and duration of study and showed no difference in serum creatinine levels, creatinine clearance, incidence of hypertension or incidence of impaired renal function. Compared with the patients in the other groups, those in Group C did not have increased incidence of progressive disease. Nevertheless, they have a higher incidence of nephrotic syndrome (p less than 0.001), a lower incidence of macroscopic haematuria (p less than 0.05), lower serum albumin (p less than 0.05) and heavier proteinuria (p less than 0.01). Severity of proteinuria had no significant correlation with the severity of renal histopathologic changes. Clinical observations divided the 24 patients with nephrotic range proteinuria into three well-defined groups with different prognoses. Six patients had progressive disease with decreasing proteinuria. Five of these remained hypertensive and their initial renal biopsy showed advanced pathologic changes. Thirteen patients had persistent proteinuria although the renal function remained unchanged. Three of these were treated with steroid but failed to respond, and their renal histopathologic changes were usually moderate. The remaining five patients showed good response to steroid treatment although two became steroid-dependent. Their renal histopathology showed mild alteration. Our findings suggest that severe proteinuria in IgA nephropathy does not inevitably indicate a poor prognosis.