Quantitative and comparative study of haematoporphyrin-derived photosensitizers on a murine tumour model

Eight commercially available HPD-photosensitizers intended for photodynamic therapy were tested in a murine tumour model with regard to their therapeutic efficacy. The regrowth delay of the fibrosarcoma SSK-2 on the mouse C3H, Neuherberg-line, was determined 3, 24, 48 and 72 h after injection of the drugs (dose: 9 mg kg^–1 body weight). The corresponding pharmacodynamics, as measured by regrowth delay, were approximated by an exponential function and the characterizing coefficients derived. These coefficients served to quantify the photodynamic properties of the drugs.The pharmacodynamics of five substances were compared with those obtained fluorometrically. The latter showed shorter decay constants than the therapy-correlated substances which indicates different metabolic behaviour of the therapeutic and diagnostically useful fluorescent components of haematoporphyrin-derived photosensitizers.     

Initial experience with carbon dioxide laser laparoscopy

Adhesions and endometriosis are commonly encountered among patients presenting with pelvic or lower abdominal pain and also in a significant proportion of infertile patients. Laparoscopic investigation is usual in patients with these problems, and it has been possible to perform endoscopic surgery with special scissors and electrodiathermy. These methods can cause troublesome bleeding, and the diathermy produces high temperatures which can be hazardous if used in the vicinity of the bowel. The carbon dioxide laser can be used endoscopically to vaporize deposits of endometriosis and adhesions with great precision and virtually no bleeding. One hundred consecutive patients with endometriosis or adhesions were treated with the CO₂ laser laparoscope and followed up for at least a year. Seventy-five per cent of patients with pain due to endometriosis were cured, and 68% of patients were better after laser laparoscopic adhesiolysis. Pregnancy rate in the previously infertile group with endometriosis was 64%. There were no complications due to the intra-abdominal use of CO₂ laser energy under endoscopic control, although there is a need for a controlled trial. It appears that in the hands of an experienced laparoscopist this technique is safe and effective.     

激光光凝治疗黄斑水肿

应用氩绿激光治疗视网膜血管性疾病所致黄斑水肿50例,73只眼。治疗后,有20.5％(15/73)的患眼视力提高2行以上,76.8％(56/73)的患眼视力保持稳定。局部性和/或非囊样黄斑水肿患眼的视力预后较好,水肿易于吸收。弥漫性和/或囊样黄斑水肿患眼的视力预后较差,水肿较难吸收。术前视力可影响预后。对激光光凝治疗本病的疗效、影响因素、激光治疗技术及其机理,也进行了讨论。     

Identification of N2 as a metabolite of acetylhydrazine in the rat

 In the pathogenesis of isoniazid-induced hepatic injury, cytochrome P450-dependent metabolic activation of the metabolite, acetylhydrazine (AcHz), is the crucial step. Exhalation of [¹⁴C]-carbon dioxide has previously been used to quantify indirectly this pathway. In contrast, according to the current concept of AcHz bioactivation, molecular nitrogen is produced directly, but has not yet been identified. Here, we measured [¹⁵N]-nitrogen and ¹⁴CO₂ exhalation, after the administration of [¹⁵N₂]-[¹⁴C]-AcHz, in rats. Laser magnetic resonance (LMR) spectroscopy, a new sensitive and specific technique for the measurement of ¹⁵N and ¹⁴N in gas samples, was used. To demonstrate the involvement of cytochrome P450, rats were treated with phenobarbital (PB) or PB + cobalt(II) chloride (CoCl₂) (n=3 in each group). Time-dependent ¹⁵N₂ exhalation differed significantly between treatment groups (p<0.001). At 240 min, cumulative exhalation of ¹⁵N was 1.92±0.43% (mean±SE) of the dose in the control group, 2.53±0.23% in the PB group, and 1.00±0.15% in the PB+CoCl₂ group (p<0.05 compared to controls, p<0.01 compared to PB). Cumulative exhalation of ¹⁴CO₂ in 24 h ranged from 15.1 to 21.9%, with no significant difference between treatment groups. In conclusion, N₂ is a metabolite of AcHz. N₂ formation reflects the cytochrome P450-mediated activation of AcHz and can be used as an index of this pathway. Generally, LMR spectroscopy is valuable for monitoring any N₂-liberating process in vivo. Received: 14 March 1995/Accepted: 15 August 1995     

Techniques in facial identification: Computer-aided facial reconstruction using a laser scanner and video superimposition

A facial image was reconstructed from the skull, part of a complete skeleton found in woodland, of a male person who had hanged himself from a tree. In addition, video superimposition was carried out with antemortem photographs of a person suspected of being the victim, and a good match was obtained. In a further case, a cheaper video-transparency superimposition was carried out, with identity later being confirmed on the basis of dental records. The techniques and the problems encountered are discussed. According to our experience, 3D computer reconstruction and video superimposition have a useful role in the process of identification, particularly in the early stages of an investigation and when other more definitive methods may not be available.     

Granular cell abrikossoff tumours of the larynx and tongue treated with the carbon dioxide (CO2) laser

Seven cases of granular cell Abrikossoff tumours of the larynx and tongue are reported: four in the tongue and three in the larynx. All of these tumours were removed with the carbon dioxide (CO₂) laser. The anatomical site of the origin and clinical features of granular cell tumours (GCT) are not specific. Histological, light microscopic, electron microscopic (EM) and immunohistochemical studies are required for diagnosis. The histogenesis and cellular derivation of GCTs is still controversial. The biological potential and lack of cellular atypia define a benign process. However, it is important to take into account that these tumours have ill-defined borders without a capsule. Radiation therapy has proved ineffective in the past. Surgical excision with a wide margin is required. Because of numerous advantages, for example, no bleeding, no oedema, minimal pain and quick recovery, CO₂ laser removal is the treatment of choice. The authors have not seen any recurrence or complications.     

Non-nociceptive capsaicin-sensitive nerve terminal stimulation allows for an original vasodilatory reflex in the human skin

A significant increase of cutaneous laser Doppler flowmetry was found before blood flow decreases with increasing pressure during a 5 mmHg min⁻¹ increase of pressure strain on the finger. Pre-treatment with a local anaesthetic or chronically applied capsaicin, resulted in the disappearance of the vasodilatory response. These results suggest an original vasodilatory axon reflex response to non-noxious pressure strain which is initiated by capsaicin-sensitive nerve terminals in the human skin.     

Alteration of pulse configuration affects the pain response during diode laser photocoagulation

Background and Objective: The shape of the treatment pulse of the diode laser (810 nm) can be easily altered electronically in contrast to ion laser photocoagulators. We investigated whether changes in laser pulse shape influenced the subjective pain response in patients undergoing retinal photocoagulation when only topical anesthesia was used. Study Design/Materials and Methods: Twenty consecutive patients required peripheral retinal photocoagulation for proliferative diabetic retinopathy or extensive retinal breaks. Three diode pulse waveforms including a square wave, shaped-wave, and an envelope of micropulses were compared to one another. Power was adjusted so that each waveform delivered the same total energy. The patients subjectively ranked the intensity of any pain they experienced for each group of lesions. Responses were compared to one another using an analysis of variance. Results: 40% of patients found the standard square wave pulse to be significantly more painful (P < 0.05) than the shaped pulse mode and 30% found the square wave significantly more painful (P < 0.05) than the micropulse mode. Conclusion: Modification of the laser pulse waveform may ameliorate pain induced by diode laser photocoagulation of the retinal periphery. © 1995 Wiley-Liss, Inc.     

Nd:YAG激光虹膜透切术治疗闭角型青光眼的临床观察研究

Nd:YAG激光虹膜透切术治疗闭角型青光眼406只眼。单脉冲激光能量为3～6mJ,平均总能量为186mJ。一次虹膜透切成功者占80.0％,二次治疗成功者为17.2％,需三次治疗者仅为2.8％。治疗后随访0.5～1.0年,眼压平均下降0.78kPa(5.87mmHg)。视力有明显提高达55.5％,保持原来视力不变者为41.0％,视力微有减退者为3.5％。治疗效果显著,无严重并发症。     

The distribution of lead in human hemopoietic tissue and spongy bone after lead poisoning and Ca-EDTA chelation therapy

Two iliac crest needle biopsies were taken from a 43-year-old lead-poisoned woman during and after completion of a Ca-EDTA treatment. By atomic absorption spectroscopy the first and second biopsy were found to contain 56, respectively 41.6 g lead/g wet tissue. In both biopsies 36% of the lead was extractable in 0.1 N HCl. Electron microbeam X-ray analysis proved to have too low sensitivity for quantitation of the lead in these biopsies. Laser microbeam mass analysis (LAMMA), performed only on the second biopsy, revealed a high and fairly constant residual lead concentration in all bone marrow cell nuclei (approximately 55 g/g) and a low lead concentration in the cytoplasm of the same cells (4–12 (g/g). The extracellular bone matrix lead was greatly concentrated in the superficial 3–6 m osteoid zone of the bony trabeculae and totally absent from deeper parts of the mineralized matrix. The LAMMA results are in good agreement with those of subcellular fractionation experiments and atomic absorption spectroscopy, provided that the relative volume fraction of nucleus and cytoplasm is accounted for. The high residual osteoid lead after completed chelation therapy indicates that lead has a stronger affinity for the organic than the mineral components of bone matrix.