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Biomedical subjects

B L Johnson

Publications and source records attributed to B L Johnson.

At least 145 records · Page 8Linked to original sources
PubMed1977

Keratoglobus and blue sclera.

Five patients from two families had similar features including keratoglobus, blue scleras, hyperextensibility of the hand, wrist, and ankle joints, sensorineural conduction hearing alterations, and mottling of the teeth. Keratoglobus had been observed in all patients at, or shortly after, birth. Corneal perforations developed in seven of the ten eyes after minimal trauma. Repair of these perforations was complicated by the extremely thin corneas and six eyes had to be either enucleated or eviscerated. Histopathological examination of two of the enucleated eyes showed the corneal stromas of both eyes to be estremely thin, Bowman's membrane was absent, and Descemet's membrane was unusually thick. This condition has an autosomal-recessive inheritance pattern.

Adolescent↗
PubMed1977

Effects of methyl n-butyl ketone behavior and the nervous system.

The effects of methyl n-butyl ketone (MBK) on nervous system function and operant behavior were investigated in monkeys and rats. Mean MBK exposure levels approximated 100 and 1000 ppm and lasted up to 10 months. Both exposures were 6 hours/day 5 days/week. Results showed that the 1000 ppm exposure effected 1) reduced motor conduction velocities in ulnar and sciatic-tibial nerves, 2) decreased the amplitude of evoked muscle action potentials, 3) lengthened implicit time of visual evoked potentials, 4) impaired operant behavioral performance, and 5) reduced body weight. Reductions in nerve conduction velocities and evoked muscle action potentials were found at 100 ppm. Recovery, as measured by sciatic-tibial nerve conduction velocity, was found to occur 6 months and 2 months after termination of the 1000 ppm and 100 ppm MBK exposures, respectively.

Action Potentials↗
PubMed1977

Comparison of oxygen uptake and heart rate during exercises on land and in water.

Oxygen comsumption and heart rate response during identical calisthenic-type exercises performed on land and in the water were compared in eight subjects. Both the heart rate and the oxygen uptake were greater during exercises in water. Although gravity is the primary resistance to movement on land, viscosity friction and turbulence are dominant resistive factors in the water. The results of this study indicate that the latter two factors provide a greater load during exercise than the resistance of gravity in land exercises. At a moderate rhythm of leg exercises, oxygen consumption increased about ten times over resting values in the water for men subjects and about seven times for women. Arm exercise performed in the water require less energy than leg exercises in water, but arm exercises require significantly more oxygen when performed in water than the same exercises performed on land.

Adult↗
PubMed1977

Endogenous Nocardia endophthalmitis: report of a case in a patient treated for lymphocytic lymphoma.

A patient with pulmonary, cerebral, and intraocular nocardiosis is reported. The intraocular disease was first recognized at autopsy. Only 7 patients with intraocular nocardiosis have been described previously. The intraocular lesions were central and paracentral, and the distribution resembled those described in 5 of the previous patients with metastatic intraocular disease. The ocular histology differed from those cases previously reported in that a granulomatous reaction accompanied the suppurative component. Malignant lymphoma treated with radiation therapy, cytotoxic drugs, and steroids formed the background against which the disease occurred in this patient.

Aged↗
PubMed1976

Peters' anomaly with the fetal transfusion syndrome.

Of identical twins with the fetal transfusion syndrome, the second twin who was anemic and hypoxemic from early gestation had Peters' anomaly by histologic examination of the host cornea excised during corneal transplantation at 7 months of age. The absence of a normally positioned lens with the incorporation of lens epithelium, capsule, and cortex within the posterior corneal stroma suggested a developmental disturbance in the separation of the lens from the cornea. The severe lenticular disturbance, microphthalmos, and fetal growth retardation in this case reflected early anemia and the resultant hypoxemia. To our knowledge, this is the first time that the fetal transfusion syndrome and Peters' anomaly have been associated.

Corneal Diseases↗
PubMed1976

Congenital epithelialization of the posterior cornea.

A 6-month-old infant boy who had a unilateral congenital corneal opacification with adhesions of abnormal iris to the posterior cornea underwent corneal transplantation. Pathologic examination of the excised cornea showed a central defect in Bowman's layer, an absent Descemet's membrane, and multilayered squamous epithelium replaced the endothelial layer. Electron microscopy confirmed that these cells had epithelial characteristics with numerous desmosomes, microvilli, and abundant cytoplasmic tonofibrils. While the pathogenesis remains obscure, a metaplastic process early in gestation probably resulted in the presence of epithelial cells in the endothelial layer.

Cornea↗
PubMed1976

Granuloma annulare.

Explore the source record for details and available documents.

Diagnosis, Differential↗
PubMed1976

Experimental endogenous endophthalmitis caused by Haemophilus influenzae type b.

Experimental endogenous endophthalmitis was produced in infant rats by either intranasal or intraperitoneal inoculation with Haemophilus influenzae type b and 5 days of age. The ocular disease occurred in about 50% of bacteremic animals who survived to age 12 days and probably represents metastatic bacterial infection secondary to hematogenous seeding. The lesion was a highly destructive suppurative endophthalmitis that ultimately progressed to panophthalmitis and was followed by organization of the exudate and phthisis bulbi.

Animals↗
PubMed1976

Pathologenesis of hematogenous bacterial meningitis in rabbits.

The authors present data obtained from a series of 27 rabbits studied following intracarotid injection of saline, brain-heart infusion broth, aerobic, or anaerobic bacteria. These data support the hypothesis that injections of cultures of both aerobic and anaerobic organisms by way of the carotid artery disrupts the blood-brain barrier over the cerebral convexities within 15 minutes; however, the inflammatory response and bacterial proliferation occur much more rapidly in the ventricular system. Within 3 hours,the barrier over the convexities is intact, but leukocytes and organisms may be seen in the long cilia of the aqeuductal region. A relative failure of leucotaxis over the convexities of the brain is the most likely explanation of these preliminary findings in this experimental model.

Animals↗
PubMed1976

A comparison of concentric and eccentric muscle training.

Eight male university students served as subjects in an investigation designed to develop strength using two different muscle training routines over a six week period. The subjects trained the arm and leg on one side of their bodies using concentric contractions and the arm and leg on the opposite side of their bodies with identical exercises using eccentric contractions. Concentric movements were against a resistance 80% of one-repetition-maximum (1-Rm) for 10 repetitions and two sets; eccentric movements were against a force of 120% of concentric 1-RM for 6 repetitions and two sets. Both routines produced significant gains in strength in all subjects, but neither training procedure produced dynamic or static strength gains significantly different from the other. Subjective evaluations by the subjects indicated that the eccentric training movements were easier to perform than the concentric training movements.

Humans↗
PubMed1976

Hyperpigmented tinea versicolor.

Examination of specimens from lesions of hyperpigmented tinea versicolor and from unaffected skin disclosed that the lesions showed increased stratum corneum turnover (8.2 +/- 0.6 vs 14.8 +/- 0.4 days, respectively), slight to moderate routine histological changes, such as acanthosis and perivascular inflammation, and dramatic electron microscopical changes (larger, singly distributed melanosomes vs small, packaged melanosomes, respectively). Brown hyperpigmentation in tinea versicolor appears to arise from an increase in melanosome size and a change in their epidermal distribution pattern.

Adult↗
PubMed1975

Prediction of locus of control orientation from the Thematic Apperception Test.

This study attempted to predict locus of control orientation from responses to the Thematic Apperception Test. Forty male and 40 female undergraduates who scored at the extremes on the Rotter Locus of Control Scale responded to TAT cards. By use of Dies' rating procedure; two judges predicted Ss' locus of control orientation with 70% accuracy. Because an external orientation was predicted with much greater efficiency than an internal orientation, it was suggested that the TAT cards may elicit more external than internal responses.

Female↗
PubMed1975

Knee joint infections with Staphylococcus aureus and Micrococcus species.

In rabbit knees 600 Staphylococcus aureus organisms produced progressive infection in 50 per cent of the knees injected, whereas 5.3 times 10-7 Micrococcus species caused only transient colonization of the joints. Methicillin, cephacetrile, and clindamycin administered before injection of the staphylococci gave protection. Stainless-steel particles in the knee did not increase susceptibility to infection from injected micrococci but did make established micrococcal infections more persistent. Knees containing steel debris failed to become infected during prolonged staphylococcal bacteremia. Injected autologous blood, either fresh or three days old, did not increase susceptibility to infection. Large doses of steroids, given systemically or intraarticularly, decreased resistance to micrococcal infection and increased the destruction caused by infection due to this organism.

Animals↗