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Biomedical subjects

J MacKenzie

Publications and source records attributed to J MacKenzie.

15 recordsLinked to original sources
PubMed1994

Hyperthyroidism secondary to a pituitary adenoma secreting TSH, FSH, alpha-subunit and GH.

A 51-year-old man had been treated for hyperthyroidism with antithyroid drugs for 8 years. He was then found to have a large pituitary adenoma with biochemical evidence of overproduction of TSH, FSH and alpha-subunit. Subsequent immunocytochemical and tissue culture studies confirmed secretion of these hormones. In addition, the tumour stained for GH and was capable of GH production in vitro. This combination of hormones produced by a pituitary adenoma has not been previously reported.

Adenoma↗
PubMed1991

Protein kinase C activation does not stimulate lung liquid clearance in anesthetized sheep.

Although active transport of ions could play an important role in the resolution process of pulmonary edema, the exact mechanism regulating this process is still unknown. In this study, we investigated the effect of phorbol myristate acetate (PMA) on lung liquid clearance in anesthetized, ventilated sheep to evaluate the possible role of protein kinase C. To study lung liquid and protein clearance, we measured the removal of 100 ml of autologous serum from the air spaces of anesthetized sheep. Either serum alone or serum mixed with PMA (10(-7) M) was instilled. After 4 h, the residual lung water was 76.8 +/- 9.2 ml when serum alone was instilled and 79.5 +/- 15.7 when serum with PMA (10(-7) M) was instilled. The lack of effect of PMA (10(-7) M) on lung liquid clearance cannot be explained by increased movement of liquid from the vascular space to the air space since we did not have any evidence of increased pressure or increased permeability in the lung. This lack of effect of PMA (10(-7) M) is not due to an absence of stimulation of protein kinase C since instillation of BSA and PMA (10(-7) M) in rat lung produced a translocation of protein kinase C activity from the cytosolic fraction to the membrane fraction 2 h after the instillation. These results were confirmed in two sheep experiments, which demonstrated clear activation of protein kinase C after 4 h. These data suggest that activation of protein kinase C does not stimulate lung liquid clearance. However, a possible role of protein kinase C in modulating lung liquid clearance has not been excluded.

Anesthesia, Intravenous↗
PubMed1990

Time trends in the prevalence of human papillomavirus infections in archival Papanicolaou smears: analysis by cytology, DNA hybridization, and polymerase chain reaction.

A retrospective study was undertaken to determine the prevalence of human papillomavirus (HPV) infections in routine Papanicolaou (Pap) smears collected by general practitioners from Western Australian women in each of the years 1972, 1982, and 1987. HPV infection was detected by cytology, dot-blot hybridization, or polymerase chain reaction (PCR). It was found that the prevalence of HPV infection remained unchanged over the 15 year study period, was independent of age, and was associated with normal cytology at a rate far greater than previously recognized. Indeed, the prevalence of cervical intraepithelial neoplasia (CIN) lesions, as detected by cytology, was 3.0% in 1972 and 3.8% in 1982 and 1987. The prevalence of HPV infection, detected as koilocytosis or parakeratosis, was 6.5%, 6.8%, and 5.3% in smears collected in 1972, 1982, and 1987, respectively, from 1,800 women. In 237 cytologically normal smears reprocessed for HPV-DNA studies, the prevalence of HPV 16 was determined to be 15.6%, 11.2%, and 17.8% in 1972, 1982, and 1987, respectively, as determined by dot-blot hybridization. However, the PCR detected HPV 16 in an additional 55.5%, 62.9%, and 57.0% of cytologically normal and dot-blot negative smears. The prevalence of HPV 16 infection in cytologically normal smears was estimated to be 71.0%, 74.1%, and 74.8% in 1972, 1982, and 1987, respectively, by combining the HPV 16 dot-blot and PCR-positive results. The high prevalence of HPV 16 in cytologically normal Pap smears suggests that infection with HPV 16, as detected by PCR amplification, does not place women in a high-risk category for cervical cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Increased sensitivity of the rapid hydrophobic grid membrane filter enzyme-labeled antibody procedure for Escherichia coli O157 detection in foods and bovine feces.

Several strains of Escherichia coli O157:H7 artificially inoculated into vegetables and dairy products were recovered on hydrophobic grid membrane filters and enumerated by an enzyme-labeled antibody assay. The mean of the recoveries from 12 fresh vegetables was 108.8%, whereas that from 10 dairy products was 93.2%. Modified tryptic soy broth at 43 degrees C with shaking at 100 rpm provided optimum recovery of the organism from meat, with a sensitivity of less than or equal to 1 CFU/g, which is 10 times more sensitive than direct plating. The method performed equally well with vegetable and dairy products. Tryptic soy broth, however, under the same conditions gave the best results for fecal samples. Of 22 asymptomatic dairy cattle, reported as having positive Brucella titers when assayed with polyclonal antibodies, eight were found to contain E. coli O157 in their feces as demonstrated by the enzyme-labeled antibody assay by using monoclonal antibodies. This finding may explain some of the false-positive Brucella tests.

Animals↗
PubMed1990

Tracheal stenosis.

A case report of tracheal stenosis is used to review the pathophysiology and surgical management of symptomatic tracheal stenosis following intubation and/or tracheostomy. The authors discuss tracheal resection and reconstruction, the preferred permanent method of managing benign tracheal stenosis.

Humans↗
PubMed1989

Lung response to test toner upon 2-year inhalation exposure in rats.

SPF F-344 rats were exposed 6 h/day 5 days/wk for up to 24 months to a special test toner at 0, 1, 4 and 16 mg/m3 or TiO2 at 5 mg/m3, or SiO2 at 1 mg/m3, by the inhalation route. The animals were kept for an additional 6 weeks in filtered air. Surviving animals were sacrificed at 25.5 months after start of exposure. Life-span and causes of death were independent of treatment and in accordance with published values. No evidence for systemic toxicity or any upper-respiratory system effects were found in the toner-exposed groups. The incidence of lung tumors was comparable in the control, 3 toner and TiO2-exposed groups. An incidence of 18%, combined benign and malignant tumors was observed in the quartz-treated rats. A slight to moderate degree of fibrosis was observed at the toner high exposure level in all animals, while a very slight degree of fibrosis was noted in 20% of the animals at the toner middle (4 mg/m3) exposure level. The fibrogenic potency of the test toner was calculated to be comparable to TiO2. No pulmonary changes were seen at the toner low (1 mg/m3) and environmentally most relevant exposure level.

Administration, Inhalation↗
PubMed1989

Phenotypical features of an unique Irish family with severe autosomal recessive osteogenesis imperfecta.

Severe Sillence type II/III Osteogenesis imperfecta (OI) is a lethal or severely crippling disease with either autosomal dominant or recessively inherited type I collagen mutations. Here we describe the detailed clinical features of a thin-ribbed OI variant with deformed limbs. The three consecutively affected children showed no genetic linkage with either of the two type I collagen genes, which implies that a novel mechanism causes this clinical phenotype. It can be prevented using ultrasound to diagnose affected foetuses.

Collagen↗
PubMed1988

Oesophageal ischaemia in motility disorders associated with chest pain.

The cause of chest pain in diffuse oesophageal spasm and "nutcracker" oesophagus is not clear. Spasm of the oesophageal muscle itself is probably not the cause, because pain and spasm are frequently not coincident. It is suggested instead that oesophageal ischaemia may be the cause of the pain, since the rewarming rate of the oesophagus after a standardised cold challenge was significantly longer in 9 patients with these motility disorders than in 21 normal controls. As rewarming time in other sites correlates with blood flow, these results are consistent with the hypothesis that the oesophagus is ischaemic in these patients.

Adult↗