Contrary response of porcine articular cartilage below and over 1000 s-1.

BACKGROUND: Knee joints experience excessive loads quite frequently during sports activities, and these shocks could accelerate progressive degeneration in articular cartilage. METHODS: Quasi-static and dynamic response of porcine knee articular cartilages were investigated in this research. Split Hopkinson Pressure Bars (SHPB) were utilized to examine the articular cartilage properties at strain rates between 0.01-2000 s-1. FINDINGS: The results showed that strain rate is an important factor for articular cartilages, distinctively divided into above and below 1000 s-1. The articular cartilages exhibit a strain hardening phenomenon when shock loaded at strain rates under 1000 s-1. When loaded at strain rates over 1000 s-1, their ultimate strength and elastic modulus decreased with increasing strain rates. INTERPRETATION: The biphasic structure of the cartilage explained the change of modulus. At the lower strain rates, fibers realigned and solidified the structure, while at higher strain rates, there is not enough time for the tissue fluid to move inside the cartilage, leading to a reduction in the deformability of the specimen and raising of Young's modulus. The results can be utilized to provide some useful data for biomaterial and computational works in the future.

Whole lung tuberculosis. A disease with high mortality which is frequently misdiagnosed.

The mortality rate of WLTB was significantly higher than non-WLTB in 45 of 516 cases of PTB in a 24-month period. There is no known underlying disease predisposing to WLTB. Clinically, the patients were significantly more toxic and had lower serum albumin and hemoglobin levels than non-WLTB patients. They had a lower rate of positive PPD tuberculin skin tests. The chest roentgenograms revealed three patterns: (1) DBS type in 15--all with multiple or diffuse opacities with or without cavitations; (2) DHS type in 20--eight with typical miliary lesions and 12 with atypical miliary patterns; (3) combined focal PTB and DHS type in ten. We found that atypical chest roentgenographic patterns were common in WLTB and frequently led to misdiagnosis. The delayed diagnosis and treatment of this advanced disease resulted in the high mortality. Early, empirical antituberculosis chemotherapy is indicated and life-saving.

Respiratory failure of acute organophosphate and carbamate poisoning.

Respiratory failure (RF) developed in 43 (40.2 percent) of 107 patients with acute organophosphate or carbamate poisoning; 22 (51.2 percent) died. The 64 patients who did not develop RF survived. All cases of RF developed within 96 hours after poisoning: within 24 hours in 35 patients (acute onset) and between 24 and 96 hours in eight patients (subacute onset). Severity of poisoning was the primary determinating factor for RF. Cardiovascular collapse and pneumonia were also associated with RF. In 19 patients with cardiovascular collapse, 17 had acute onset of RF and two had subacute onset. In 28 patients with pneumonia, 17 developed acute onset of RF and eight developed subacute onset. No organophosphorus compound caused RF more frequently than another. The duration of ventilator support for subacute RF was significantly longer than for acute RF (287 +/- 186 vs 115 +/- 103 hours, p = 0.02). The use of pralidoxime did not reduce the incidence of RF. We found that severity of poisoning, cardiovascular collapse, and pneumonia were the predisposing factors to RF. The golden time for treatment of acute organophosphate or carbamate poisoning was the initial 96 hours. No RF occurred after this time. Aggressive treatment and prevention of the above three factors will reduce the incidence of RF, or in other words, reduce the mortality.

Pneumonia preceding respiratory failure. A rare, easily misleading clinical manifestation in adult Arnold-Chiari malformation.

A 47-year-old woman was admitted for bilateral lower lobe pneumonia with respiratory distress. Two episodes of respiratory failure developed despite improvement of pneumonia after antibiotic chemotherapy. Loss of consciousness and quadriplegia accompanied the last episode of respiratory failure. Arnold-Chiari malformation type 1 was diagnosed and a suboccipital craniectomy was performed. The neuromuscular and respiratory disorders greatly improved after operation. We believe that ACM 1 should be considered when an adult develops unexpected respiratory failure after improvement of the primary pulmonary condition. This disease is potentially treatable by surgical management, and if it is misdiagnosed, will be fatal.

Leiomyoma of the bronchus: report of a case successfully treated by Nd-YAG laser via fiberoptic bronchoscope.

A 42-year-old woman presented with chronic cough and dyspnea. A leiomyoma of the right middle lobe of the bronchus was diagnosed by bronchoscopic biopsy and treated successfully by neodymium-yttrium aluminum garnet laser, via fiberoptic bronchoscope. The presentations of bronchial leiomyoma are mainly due to partial or complete occlusion of the involved bronchus. Symptoms are mainly cough, wheeze, chest pain and fever, as a result of atelectasis, consolidation, collapse or bronchiectasis. The management of this benign tumor of the lung is discussed, and the importance of early diagnosis and conservative therapy are emphasized.

Acute renal failure and severe thrombocytopenia induced by rifampicin: report of a case.

We report on a patient who developed life-threatening thrombocytopenia and acute renal failure after the reinstitution of rifampicin therapy for pulmonary tuberculosis. This combined reaction is rarely reported. Supportive treatment and withdrawal of rifampicin led to complete recovery. The increased incidence of drug-resistant tuberculosis and the need for the reintroduction of rifampicin therapy may lead to more such reactions being observed.

Mycobacterium fortuitum mastitis following augmentation mammaplasty: report of a case.

A 26-year-old woman was admitted to the Veterans General Hospital with the chief problem of recurrent abscess formation over the right breast one month after augmentation mammaplasty. Pus aspirated from the right breast grew Mycobacterium fortuitum, a rapidly growing atypical Mycobacterium, in 4 consecutive cultures. The infected mammanoplastic prosthesis was surgically removed. Acid-fast bacilli were found on pathologic examination of the surgical specimen. Amikacin, doxycycline and ethambutol were given for two weeks according to the sensitivity test. The patient underwent reconstructive surgery of her right breast 10 months later. A specimen obtained from that surgery showed no more acid-fast bacilli on pathological examination. To date there are no signs of recurrence. We suggest that the possibility of mycobacterial infection should be kept in mind when the pus is reported as being "sterile" on an ordinary bacterial culture.

Ludwig's angina: an analysis of 14 cases.

Ludwig's angina remains a potentially lethal disease entity as it causes rapidly progressive airway obstruction, although the current mortality rate is low. Early surgical intervention should be carried out in severe cases which show signs of fluctuation, abscess formation or other serious complications. We report our experience with 14 cases of Ludwig's angina, 12 of which (86%) were of dental origin. Only one case was complicated with Klebsiella pneumoniae septicemia which resolved upon treatment. There were no deaths. Surgical procedures including incision and drainage and tooth extraction were performed in 11 cases (78%). Antibiotics were administered to all patients. Most of them were treated with crystalline penicillin with or without an aminoglycoside. Only one patient received a tracheostomy in this series. The number of tracheostomies or intubations carried out was much lower than in previous reports. We suggest that an aggressive antimicrobial therapy, early surgical intervention and careful monitoring of the respiratory symptoms would reduce both the need for tracheostomy and the mortality rate.

Mycoplasma pneumoniae pneumonia: clinical analysis of 45 cases.

Mycoplasma pneumoniae (M. Pneumoniae) is a primarily pathogen of the respiratory tract. The clinical characteristics, laboratory findings, and roentgenographic patterns of 45 patients with serologically proven M. pneumoniae pneumonia admitted to Chang Gung Hospital from 1981 to 1989 have been reviewed. There were 23 males and 22 females. Forty-one (91%) were below 40 years old and 13 patients (29%) were below 5 years old. Fever, cough and chest rales were the most common symptoms and signs. A transient mild elevation of liver enzymes was seen in 33% of the patients, most of whom were below the age of ten (73%). A leukocyte count over 15,000/cu mm was not rare (16%). Roentgenographic features included unilateral infiltration (84%), lower lobe predominance (60%), and either confluent (56%) or patchy (33%) consolidation. Pleural effusion occurred in 24% of the patients. Complete resolution of chest roentgenography took from 8 to 42 days with a mean of 20 days. The response of fever to treatment with erythromycin took from 1 to 6 days with a mean of 3 days. There were no life threatening pulmonic or extrapulmonic complications.