Search PubMed⌕ Search

Biomedical subjects

T Kahn

Publications and source records attributed to T Kahn.

At least 127 records · Page 7Linked to original sources
PubMed1987

Selective digital subtraction arteriography in necrosis of the femoral head.

Selective digital subtraction arteriographic investigations of the arteries of the femoral head in 31 patients with traumatic and 34 patients with nontraumatic femoral head necrosis (FHN) were compared with investigations in a control group of 35 patients without hip disease. In the control group and in patients with nontraumatic FHN atypical arteriographic findings were found only in one third of cases. In traumatic FHN, however, vascular alterations could be detected in 97% of cases. This evidence suggests that damage to the femoral head vessels is a major etiological factor in traumatic, but not in nontraumatic, FHN. In late arterial phases of DSA a perinecrotic hypervascularization was the common feature in all nontraumatic necroses and could be observed in 71% of traumatic necroses. Its pathophysiological mechanism is discussed.

Adolescent↗
PubMed1987

Age-related morphology of the normal pancreas on computed tomography.

Abdominal computed tomographic scans were performed on a group of 360 patients between the ages of 20 and 80 years. The anteroposterior diameter of the pancreatic head, body, and tail, the age-related ratio of vertebral body-pancreas diameter, and the external and internal contours of the organ were analyzed. The age-related changes in the pancreas were compared with known anatomical findings.

Adult↗
PubMed1987

[The MRT demonstration of bone marrow changes in intervertebral disk degeneration].

Amongst 214 patients with degenerative disc disease, MRT showed focal fat deposition in the vertebral marrow close to the end plate in 87 (41%). The appearances and distribution of these zones is described. Recognition of these common changes is important in differential diagnosis between inflammatory and neoplastic processes.

Bone Marrow↗
PubMed1986

Molecular cloning and characterization of the DNA of a new human papillomavirus (HPV 30) from a laryngeal carcinoma.

DNA from a human laryngeal carcinoma was molecularly cloned in Lambda L47. The gene library was screened for human papillomavirus (HPV)-related sequences by hybridization analysis with 32P-labelled HPV 16 DNA at conditions of low stringency (Tm -40 degrees C). One of the clones (4-5) with an insert of 7.8 kb showed cross-hybridization with most of the known HPV types (Tm -40 degrees C), and with several of them even under more stringent conditions (Tm -30 degrees C). No signal was detected under high-stringency conditions (Tm -20 degrees C). The co-linear alignment of clone 4-5 with HPV 16 DNA could be demonstrated by hybridization experiments and also by partial DNA sequence analysis. We conclude that clone 4-5 represents a new HPV type tentatively designated HPV 30. HPV 30 DNA was also detected in 2 genital lesions but not in 41 laryngeal carcinomas analyzed so far. Its presence in other tumor DNA is now under investigation.

Base Sequence↗
PubMed1986

[Diagnosis of spondylitis by MR tomography].

The results of MR tomography in 13 patients with specific and nonspecific spondylitis are reported. There were characteristic changes in signal intensity and in the configuration of the vertebral bodies and the intervertebral discs. The extent of intraspinal stenosis can be demonstrated accurately by MR. Paravertebral abscesses can be shown accurately and their position can be clarified by means of multiplanar sections. The early diagnosis of spondylitis by MR tomography is discussed.

Adult↗
PubMed1986

[DSA of the pulmonary vessels during endobronchial laser- and afterloading therapy of malignant bronchial stenoses].

The findings are reported of the DSA examination of the pulmonary vessels in 16 patients with malignant bronchial stenoses, for whom laser or after-loading therapy was being considered. In these patients an improvement of dyspnoea can be expected only of there is adequate perfusion of the involved lung segment. DSA demonstrated stenoses or occlusions of main pulmonary or lobar arteries in six patients. Ten patients had a normal pulmonary circulation. In most cases the result of the DSA examination was important in determining treatment.

Aged↗
PubMed1986

[Findings of NMR tomography in the diagnosis of osteomyelitis and arthritis].

The findings on MR tomography in fourteen patients with osteomyelitis and eight patients with arthritis are described. A retrospective analysis showed that MR was superior in demonstrating changes in the bone marrow and spread of infection round the bone. These changes are shown more accurately and with better contrast after the use of gadolinium DTPA. T1 and T2 sequences appear to be necessary.

Abscess↗
PubMed1986

Calcium channel blockers enhance extrarenal potassium disposal in the rat.

The effect of calcium channel blockers on the extrarenal disposition of an acute potassium load was examined in acutely nephrectomized rats infused with KCl (0.75 meq X kg-1 X h-1 for 60 min) alone or in combination with either verapamil or nifedipine. The increment in plasma potassium concentration during the potassium infusion (delta PK) with either verapamil or nifedipine was less than control (P less than 0.05 and 0.01, respectively). Studies were repeated in acutely adrenalectomized rats (ADX) to evaluate whether the changes in plasma potassium were consequent to the enhanced activity of epinephrine and other adrenal hormones. delta PK with ADX was higher than control (P less than 0.01). Verapamil or nifedipine with ADX resulted in a lower delta PK than ADX alone (P less than 0.05). Further studies were then conducted with the selective beta 2-adrenergic blocker butoxamine hydrochloride to rule out enhanced peripheral sympathetic activity of the beta 2-adrenergic system in facilitating the potassium disposal. delta PK with butoxamine was greater than control (P less than 0.01) but not significantly different from ADX. Verapamil or nifedipine in conjunction with butoxamine resulted in a lower delta PK than butoxamine alone (P less than 0.01). Changes in arterial pH and plasma bicarbonate were similar in all groups. In conclusion, during potassium infusion the delta PK is lower in the presence of calcium channel blockers. The alteration in potassium transport produced by calcium channel blockers does not appear to be dependent on adrenal function or peripheral sympathetic activity. Impaired calcium entry into cells may alter potassium transport in the intact animal.

Adrenalectomy↗
PubMed1986

[Combination of bilateral idiopathic necrosis of the femoral and humeral heads--initial report of a syndrome].

The authors report on a patient of 31 years of age with bilateral necroses of the head of the femur and of the humerus. Internistic and neurological examinations did not yield any pointer to an existing symptomatic bone necrosis, so that this case--not described in literature so far--represents an aseptic, idiopathic necrosis of both femoral and humeral heads. The findings obtained with plain radiography, computed tomography, selective angiography of the femoral head and magnetic resonance tomography are presented.

Adult↗
PubMed1986

Congestive heart failure with hypernatremia.

A patient presented with hypernatremia (plasma sodium level equals 171 mEq/L), marked congestive heart failure, and fluid retention. A high-salt intake and an inappropriate lack of thirst in this patient with poor cardiac function resulted in hypernatremia accompanied by edema. Hypertonic salt intake may have been due, in part, to zinc deficiency.

Heart Failure↗
PubMed1985

Kinetics of Cl-dependent K influx in human erythrocytes with and without external Na: effect of NEM.

The majority of the ouabain-insensitive K influx in human erythrocytes is dependent on the presence of Cl. Recent studies have shown that a portion of the Cl-dependent K influx persists in the absence of external Na (Nao). It has been suggested that this Nao-independent component represents (K + Cl) cotransport, whereas the remainder of the Cl-dependent K influx seen on addition of external Na represents (Na + K + 2Cl) cotransport. In the present studies, the kinetics of Cl-dependent K influx were examined in the presence and absence of external Na, by varying external K and external Cl. Our studies suggest that the Nao-independent Cl-dependent pathway has a relatively low affinity for external K (Km 17-30 mM) in contrast to the high affinity of the Nao-augmented component (Km 3-4 mM). N-ethylmaleimide (NEM) stimulates the maximal velocity of the Nao-independent Cl-dependent K influx achievable without alteration of intracellular solutes but does not alter its Km for external K. In contrast, NEM has no stimulatory effect on the Nao-augmented component. The Cl dependence of the Nao-independent K influx is best described by a relatively flat curve with a mild upward concavity. The kinetic properties of the Nao-independent component of Cl-dependent K transport are very similar to those of the putative (K + Cl) cotransport pathway seen in low-K sheep erythrocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological Transport↗
PubMed1985

Role of citrate excretion in acid-base balance in diuretic-induced alkalosis in the rat.

Studies were performed to assess the role of changes in the excretion of citrate, a metabolic precursor of bicarbonate, in acid-base balance in diuretic-induced metabolic alkalosis. Rats on a low-chloride diet with sodium sulfate added were studied during a base-line period, 3 days of furosemide administration, and 4 days post-furosemide. During the period of furosemide administration, net acid excretion and plasma bicarbonate concentration increased. In the post-furosemide period, net acid excretion remained higher than base line but plasma bicarbonate concentration did not increase further. Citrate excretion was significantly higher in the post-furosemide period than in base line. Studies substituting sodium neutral phosphate or sodium bicarbonate for dietary sodium sulfate demonstrated greater increases in net acid excretion post-furosemide and, again, no increase in plasma bicarbonate concentration during this period. Citrate excretion was greater than in the sulfate group. The increment in citrate excretion was proportional to the base "load," defined with respect to changes in net acid excretion and/or dietary bicarbonate. Thus, in these studies alterations of base excretion in the form of citrate play an important role in acid-base balance during diuretic-induced metabolic alkalosis.

Acid-Base Equilibrium↗
PubMed1984

Carbon dioxide removal in acetate hemodialysis: effects on acid base balance.

Studies were performed in patients on maintenance acetate hemodialysis to assess the quantity and processes involved in the removal of carbon dioxide (CO2) during the treatment. For this purpose the CO2 losses from whole blood were evaluated in vivo using a mass balance technique. The data demonstrated that the CO2 recovered in the dialysate exceeded the amount calculated to have left the blood in the same period. This observation suggested that CO2 may be generated by the blood cells as they go through the dialyzer. In vitro studies confirmed this observation and established that the uremic blood cells can generate CO2 when exposed to a low PCO2 and/or HCO3. The net effect of this CO2 generation may be hydrogen ion gain by the patient. The contribution of ultrafiltration to the losses of CO2 depends on the volume of ultrafiltrate and the plasma HCO3 concentration. The dialysance of total CO2 was found to be equal to that of urea nitrogen. Treatments with high urea dialysance may interfere with the acute and chronic correction of the acid base balance in these patients. The data presented suggest that multiple factors related to the removal of CO2 during acetate dialysis may be responsible in part for the low plasma bicarbonate observed in patients on chronic maintenance hemodialysis.

Acetates↗
PubMed1984

Mechanism of alteration of sodium potassium pump of erythrocytes from patients with chronic renal failure.

We examined intracellular electrolytes, K influx, and [3H]ouabain-binding capacity of erythrocytes from 32 normal subjects and 45 patients with end-stage renal failure on dialysis, including 16 with high intracellular Na (mean 17.3 +/- 3.9 mmol/liter cell water). The [3H]ouabain-binding capacity of erythrocytes with high cell Na was markedly reduced as compared with that of erythrocytes from normal subjects (274 +/- 52 vs. 455 +/- 59 sites/cell, P less than 0.001). The mean serum creatinine was higher in the uremic group with high cell Na. There was a significant linear correlation between intracellular Na and [3H]ouabain-binding in both normal and uremic subjects. Cross-incubation of normal cells with uremic plasma for 24 h failed to reduce [3H]ouabain-binding capacity of normal cells. In spite of a substantial increase in cell Na, K pump influx was not higher in uremic erythrocytes with high cell Na. When intracellular Na was altered with nystatin (cell Na equal to 120 mmol/liter cell water in both groups), K pump influx was proportional to the number of Na-K pump sites so that the ion turnover rate per pump site was similar in the two groups. Uremic plasma failed to depress K pump influx of normal erythrocytes. The passive net influx of Na in uremic cells with high intracellular Na was not different from that observed in erythrocytes from normal subjects. When erythrocytes were separated by age on Percoll density gradients, the number of Na-K pump sites of the youngest uremic cells was significantly lower than that of the youngest normal cells, suggesting that decreased synthesis of Na-K pump sites, rather than accelerated loss of Na-K pump sites during aging, was responsible for the decrease in [3H]ouabain-binding capacity of erythrocytes from uremic subjects. Taken together, these findings suggest that a decrease in the number of Na-K pump sites plays a major role in the abnormality of Na-K pump of erythrocytes from patients with chronic renal failure.

Adult↗